Risk factors associated with Campylobacter jejuni infections in Curaçao, Netherlands Antilles

Campylobacter genotypes from food animals, environmental sources and clinical disease in Scotland 2005/6

A nationwide multi-locus sequence typing (MLST) survey was implemented to analyze patterns of host association among Campylobacter jejuni and Campylobacter coli isolates from clinical disease in Scotland (July 2005-September 2006), food animals (chickens, cattle, sheep, pigs and turkey), non-food animals (wild birds) and the environment. Sequence types (STs) were determined for 5247 clinical isolates and 999 from potential disease sources (augmented with 2420 published STs). Certain STs were over represented among particular sample sets/host groups. These host-associated STs were identified for all sample groups in both Campylobacter species and host associated clonal complexes (groups of related STs) were characterized for C. jejuni. Some genealogical lineages were present in both human disease and food animal samples. This provided evidence for the relative importance of different infection routes/food animal sources in human disease. These results show robust associations of particular genotypes with potential infection sources supporting the contention that contaminated poultry is a major source of human disease.

Comparative genomic analysis of Campylobacter jejuni associated with Guillain-Barré and Miller Fisher syndromes: neuropathogenic and enteritis-associated isolates can share high levels of genomic similarity

Background

Campylobacter jejuni infection represents the most frequent antecedent infection triggering the onset of the neuropathic disorders Guillain-Barré syndrome (GBS) and Miller Fisher syndrome (MFS). Although sialylated ganglioside-mimicking lipo-oligosaccharide (LOS) structures are the strongest neuropathogenic determinants in C. jejuni, they do not appear to be the only requirement for a neuropathic outcome since strains capable of their production have been isolated from patients with uncomplicated cases of enteritis. Consequently, other pathogen and/or host-related factors contribute to the onset of neurological complications. We have used comparative genomic hybridization to perform a detailed genomic comparison of strains isolated from GBS/MFS and enteritis-only patients. Our dataset, in which the gene conservation profile for 1712 genes was assayed in 102 strains, including 56 neuropathogenic isolates, represents the largest systematic search for C. jejuni factors associated with GBS/MFS to date and has allowed us to analyze the genetic background of neuropathogenic C. jejuni strains with an unprecedented level of resolution.

Results

The majority of GBS/MFS strains can be assigned to one of six major lineages, suggesting that several genetic backgrounds can result in a neuropathogenic phenotype. A statistical analysis of gene conservation rates revealed that although genes involved in the sialylation of LOS structures were significantly associated with neuropathogenic strains, still many enteritis-control strains both bear these genes and share remarkable levels of genomic similarity with their neuropathogenic counterparts. Two capsule biosynthesis genes (Cj1421c and Cj1428c) showed higher conservation rates among neuropathogenic strains compared to enteritis-control strains. Any potential involvement of these genes in neuropathogenesis must be assessed. A single gene (HS:3 Cj1135) had a higher conservation rate among enteritis-control strains. This gene encodes a glucosyltransferase that is found in some of the LOS classes that do not express ganglioside mimics.

Conclusion

Our findings corroborate that neuropathogenic factors may be transferred between unrelated strains of different genetic background. Our results would also suggest that the failure of some strains isolated from uncomplicated cases of enteritis to elicit a neuropathic clinical outcome may be due to subtle genetic differences that silence their neuropathogenic potential and/or due to host-related factors.

The microarray data has been deposited in NCBI's Gene Expression Omnibus under accession number GSE3579.

Molecular mimicry in Campylobacter jejuni: role of the lipo-oligosaccharide core oligosaccharide in inducing anti-ganglioside antibodies

Campylobacter jejuni is recognized as the most common identifiable pathogen associated with the development of Guillain-Barré syndrome (GBS), an acute autoimmune-mediated disease affecting the peripheral nervous system. The immune response to ganglioside-like structures in lipo-oligosaccharides (LOSs) of certain C. jejuni strains is thought to cross-react with human nerve gangliosides and induce GBS. To study the involvement of LOSs in the pathogenesis of Campylobacter-induced GBS, we created truncated LOS molecules by inactivating the waaF gene in a GBS-associated isolate of C. jejuni. Gas Chromatography-MS analysis of the waaF mutant LOSs revealed a marked reduction in sugar content, including sialic acid and galactose. GM1 and GD1a-like mimicry was not detected in the waaF mutant by Western blot analysis with cholera toxin B and anti-GD1a antibodies. Mice immunized with the waaF mutant failed to develop anti-GM1 or anti-GD1a antibodies. The waaF mutant also showed reduced adherence to and invasion of INT-407 cells. The results indicate that the LOS of C. jejuni HB93-13 is essential for adherence and invasion as well as for anti-ganglioside antibody induction.

Campylobacters as zoonotic pathogens: a food production perspective

Campylobacters remain highly important zoonotic pathogens worldwide which infect an estimated 1% of the population of Western Europe each year. Certain campylobacters are also important in infections of animals, particularly of the reproductive tract, and some are involved in periodontal disease. This paper focuses, however, on the two species which are most important in food-borne infections of humans, Campylobacter (C.) jejuni and C. coli. Infection with these campylobacters is serious in its own right but can also have long-term sequelae such as reactive arthritis and Guillain-Barré syndrome. The pathogens are ubiquitous in nature and in domestic animals and, as a consequence, are found frequently in the environment and on many raw foods, of both plant and animal origin and bacterial numbers can be very high on certain key foods like raw poultry meat. Although all commercial poultry species can carry campylobacters, the risk is greater from chicken because of the high levels of consumption. Campylobacters are relatively 'new' zoonotic pathogens as routine culture from clinical specimens only became possible in the late 1970s. As a consequence there is much that still needs to be understood about the behaviour and pathogenicity of these highly important bacteria. In particular, and from a food industry/food safety perspective, it is important to better understand the behaviour of C. jejuni and C. coli in the food production environment, and how this affects their ability to survive certain food production processes. There is a belief that campylobacters are much more sensitive to hostile conditions than either salmonellas or Escherichia coli. Much of data to support this view have been derived from laboratory experiments and may not fully represent the natural situation. Studies are showing that campylobacters may be more robust than previously thought and thus may represent a greater challenge to food safety. We recommend that research is undertaken to better understand how campylobacters behave in the food chain and how responses to relevant conditions affect their ability to survive processing and their virulence. There is also a need to better understand the reasons why campylobacters are capable of frequent change, particularly in the expression of surface antigens.

Sporadic campylobacter infection in infants: a population-based surveillance case-control study

BACKGROUND

Campylobacter is an important cause of foodborne illness in infants (younger than 1 year of age), but little is known about the sources of infection in this age group.

METHODS

Eight sites in the Foodborne Diseases Active Surveillance Network (FoodNet) participated in a 24-month population-based case-control study conducted in 2002-2004. Cases were infants with laboratory-confirmed Campylobacter infection ascertained through active laboratory surveillance, and controls were infants in the community.

RESULTS

We enrolled 123 cases and 928 controls. Infants 0-6 months of age with Campylobacter infection were less likely to be breast-fed than controls [odds ratio (OR); 0.2; 95% confidence interval (CI), 0.1-0.6]. Risk factors for infants 0-6 months of age included drinking well water (OR 4.4; CI, 1.4-14) and riding in a shopping cart next to meat or poultry (OR 4.0; CI, 1.2-13.0). Risk factors for infants 7-11 months of age included visiting or living on a farm (OR 6.2; CI, 2.2-17), having a pet with diarrhea in the home (OR 7.6; CI, 2.1-28) and eating fruits and vegetables prepared in the home (OR 2.5, CI 1.2-4.9). Campylobacter infection was associated with travel outside the United States at all ages (OR 19.3; CI, 4.5-82.1).

CONCLUSIONS

Several unique protective and risk factors were identified among infants, and these risk factors vary by age, suggesting that prevention measures be targeted accordingly. Breast-feeding was protective for the youngest infants and should continue to be encouraged.

Campylobacter jejuniisolated from retail poultry meat, bovine feces and bile, and human diarrheal samples in Japan: Comparison of serotypes and genotypes

To determine the significance of poultry and bovine as infectious sources of Campylobacter jejuni in Japan, the serotype distribution and pulsed-field gel electrophoresis (PFGE) patterns of poultry and bovine isolates were compared with those of isolates from patients with diarrhea in Akita (Japan). Serotypes O:2 and O:4-complex were common in human, poultry, and bovine isolates, and serotype O:23,36,53 was common in human and bovine isolates. SmaI PFGE patterns of isolates belonging to these serotypes were generated. Eight PFGE patterns were shared by poultry and human isolates and three patterns were shared by human and bovine isolates. Further analysis of the isolates having the same SmaI PFGE pattern by KpnI PFGE confirmed that four patterns and two patterns were still shared by poultry and human isolates, and bovine and human isolates, respectively. Thus, serotypic and genotypic data indicated a possible link between sporadic human campylobacteriosis and C. jejuni from retail poultry and bovine bile and feces, suggesting that bovine serves as an infectious source of C. jejuni in Japan, as is observed in other countries.

Pet dogs and chicken meat as reservoirs of Campylobacter spp. in Barbados

Campylobacter spp. are the second most common pathogen isolated from stools of patients with gastroenteritis in Barbados. The aim of this study was to identify reservoirs of Campylobacter and the likely source(s) of human infection. Fecal specimens from 596 animals and 311 samples of animal food products were analyzed for the presence of Campylobacter spp. by standard culture techniques. Isolates were characterized by conventional phenotypic tests, confirmed by latex agglutination and PCR with genus-specific primers, and identified by the use of species-specific primers. High isolation rates were obtained for chickens (94.2%), pigs (90.5%), dogs (46.9%), cats (37.3%), and wild birds (39.3%). Campylobacter was also recovered from monkeys (17.1%) and sheep (4.2%) but not from cows. Chicken meat was frequently contaminated with Campylobacter (58.4%), but its recovery from other animal food products was rare. Campylobacter jejuni was the most commonly identified species in humans (63.6%), chickens (86.6%), dogs (51.5%), and chicken meat (79.8%). Porcine isolates were predominantly C. coli (98.4%), while cats harbored mainly C. upsaliensis and C. helveticus. Wild birds alone carried urease-positive thermophilic campylobacters. C. jejuni and C. coli isolates from different sources were compared with isolates from humans by randomly amplified polymorphic DNA typing with the primers OPA 11 and HLWL 85. Genotyping revealed similarities between isolates from chicken meat and those from humans and could not distinguish between two clinical isolates and four canine strains. Our results suggest that dogs are significant reservoirs of Campylobacter and contribute to human enteric infections and that chicken meat is a likely vehicle for the transmission of campylobacters to humans.